There are many different signal standards used for television broadcasting in various countries. For example, the frame frequency is 30 Hz in the United States and Japan, and 25 Hz in England and Continental Europe. The number of horizontal lines per frame is 525 in the United States and Japan, and 625 in Europe and many other countries. Therefore, when a prerecorded television program is exchanged between such countries which have different frame and/or line frequency standards, a frequency conversion must be provided. Various schemes have been devised in the prior art for converting between the field or frame rates and the line rates of the various television signal standards. However, these schemes require multiple frame stores and sophisticated signal processing hardware to achieve the conversion because of the differences in horizontal, vertical, and frame rates. Such "standards converters" are extremely expensive.
It is therefore desirable to provide a less expensive means of converting the standard of a prerecorded television signal to that of another standard.